Making another brittle test related to log assertion more robust

[amoghrajesh]

======================================================================================== short test summary info =========================================================================================
FAILED providers/apache/flink/tests/unit/apache/flink/sensors/test_flink_kubernetes.py::TestFlinkKubernetesSensor::test_driver_logging_completed - assert equals failed
  'Flink application ended successfully'                                                        "2022-09-25 19:01:47,027 INFO  KubernetesTaskExecutorRunner [] - ---------\nSuccessful regis 
                                                                                                tration at resource manager akka.tcp://flink@basic-example.default:6\nReceive slot request 8 
                                                                                                0a7ef3e8cc1a2c09b4e3b2fbd70b28d for job 363eed78e59\nCheckpoint storage is set to 'jobmanage 
                                                                                                r'\nFlat Map -> Sink: Print to Std. Out (2/2)#0 (e7492dc4a) switched to RUNNING."
============================================================ 1 failed, 13193 passed, 3707 skipped, 1 xfailed, 5 warnings in 630.90s (0:10:30) ============================================================

related to #53743

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[potiuk]

Nice... Was about to look at this one :)

[kyungjunleeme]

This kind of code style is one of the strengths of writing tests with pytest — just like we discussed in the thread.

[amoghrajesh]

Precisely, I used the suggestions we had in the email thread and it worked well!

[potiuk]

Yep - very nice :)